Which unit of measurement is commonly used to assess loudness perception across various frequencies?

The unit of measurement commonly used to assess loudness perception across various frequencies is the phon. The phon scale is specifically designed to reflect perceived loudness, as it takes into account the frequency sensitivity of human hearing. This means that a sound measured in phons corresponds to the loudness level perceived by a listener, which allows for comparisons of loudness regardless of the frequency at which the sound occurs.

This measurement is particularly useful in the context of psychoacoustics, the branch of study focused on how humans perceive sound. The phon scale is aligned with the decibel scale at a reference frequency (1 kHz), making it a valuable tool for accurately representing how loud different sounds are perceived by individuals across the frequency spectrum.

In contrast, decibels measure sound intensity, and while they provide a vital reference for sound levels, they do not directly convey the perceived loudness, especially across different frequencies. Sones, on the other hand, are related to the concept of loudness but represent a different scale where 1 sone is perceived as equal to a 1 kHz tone at 40 dB. Lastly, the bel is a unit that is less commonly used today, and it is primarily used to express large ratios of power in